Circuit for hydraulically operable devices,especially hydraulic dredges



Nov. 18, 1969 J GERBER Em 3,4784647 CIRCUIT FOR HYDRAULiICALLY OPERABLE DEVICES, ESPECIALLY HYDRAULIC DREDGE Filed March 11, 1968 s 3 Sheets-Sheet l FIG.1

INVENTORS Nov. 18, 1969 3 8 J. GERBER ErAL ,47 ,647 CIRCUIT FOR HYDRAULICALLY OPERABLE DEVICES, SP ALLY Filed March 11, 1968 HYDRAULIC DRE-MES s Sheets-Sheet 2 INVENTORS:

NOV. 18, J. GERBER ETAL CIRCUIT FOR HYDRAULICALLY OPERABLE DEVICES, ESPECIALLY HYDRAULIC DREDGES Flled March 11, 1968 3 Sheets-Sheet 5 FIG? 51 INVENTOR 5 E78 51-20;- 7'77'6drz'r/ 7754/09 United States Patent 3,478,647 CIRCUIT FOR HYDRAULICALLY OPERABLE DE- VICES, ESPECIALLY HYDRAULIC DREDGES Jiirgen Gerber, Dortmund-Bodelschwingh, and Friedrich Fichtner, Bochum-Weitmar, Germany, assignors to Orenstein-Koppel und Lubecker Maschinenbau Aktiengesellschaft, Dortmund-Dorstfeld, Germany Filed Mar. 11, 1968, Ser. No. 712,189 Claims priority, applicgtiglzl Germany, Mar. '10, 1967,

Int. Cl. F15b 11/10, 13/042; F02b 73/00 US. Cl. 91-411 9 ABSTRACT OF THE DISCLOSURE Hydraulic circuit for implements such as a dredge in which a pair of pumps supply a plurality of motors via a control valve for each motor with a bypass channel leading from said pumps to exhaust via said valves and which bypass channel is interrupted when any valve is shifted from its neutral position. A second channel leads from each pump to the inlet of some of the control valves and is interruptedupon shifting of any of the control valves and on the downstream side of the shifted control valve.

is passed through other valves. For each double-acting consumer, two 4-way valves are required. These 4-way valves have to be actuated individually in conformity with the desired oil supply to the individual consumers. Such an arrangement requires a considerable number of servicing elements.

It is, therefore, an object of the present invention to provide a control circuit for hydraulically operable devices, which will overcome the above-mentioned drawback.

It is another object of this invention to provide a simple control circuit requiring only a few actuating elements, in which for purposes of obtaining high working speeds when actuating one cylinder only, the said cylinder will receive the delivery of both pumps whereas when actuating an additional cylinder, each cylinder will automatically receive the delivery of one pump only while the control of the oil motors for the driving and swinging mechanism, in a manner known per so, will be effected independently of each other from one associated pump only.

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawing, in which:

FIGURE 1 represents a control circuit according to the present invention;

FIGURE 2 is a partial longitudinal section through a control valve with the particular guiding means for the control oil according to the present invention; and

FIGURE 3 is a partial section through a control valve preceded by an auxiliary control valve.

The problem underlying the present invention has been solved in conformity with the present invention by an arrangement according to which the control conduits which control the pressureless circulation of the pumps (1, 2) and are provided with check valves are after the passage through the precontrolled pressure limiting valves combined with the control valves associated with the driving 3,478,647 Patented Nov. 18, 1969 "ice mechanisms and the swinging mechanisms so as to form a common control conduit which latter after passing through the control valves which are associated with the Working devices will in idling condition of the circuit return the control oil to an oil reservoir whereas when actuating one control valve or a plurality of control valves the delivery to the oil reservoir will be blocked.

Advantageously, according to a further development of the present invention, the control of the control oil is effected through the intervention of an auxiliary piston which is displaceably arranged in a control bushing which axially precedes the control housing of the control valve and simultaneously serves as housing. The advantage of this arrangement consists in that ordinary mass produced 6- way valves can be employed instead of expensive special valves so that it is also possible to equip already produced devices of the type involved with the circuit according to the present invention.

Referring now to the drawings in detail, the pumps 1 and 2 produce the pressure oil for actuating the right and left driving mechanisms 3, 4 when the dredge is equipped with a track-laying drive. The pumps 1 and 2 furthermore produce the pressure oil for actuating the swinging mechanism 5 and the cylinders 6, 7 and 8 for respectively actuating the boom, the dipper arm and the digging vessel or bucket of the dredge. The two driving mechanisms 3 and 4 and the swinging mechanism 5 receive the pressure oil through control valves 9, 10 and 11. The cylinders 6, 7 and 8 receive the pressure oil for actuating the same through associated control valves 12, 13 and 14. Pump 1 has associated therewith a relief valve 16 from where the control oil, in case no consumers are to be actuated, passes through the check valve 17, the valves 9 and 11, and the control conduit 18 whereas the control oil from the relief valve 15 passes through the check valve 19, control valve 10 and control conduit 20. The two control conduits 18 and 20 unite so as to form the control conduit 21. As long as the control valves 12, 13 and 14 occupy their neutral position, the control oil will in a pressureless condition pass to the oil reservoir 25 through the passages 22, 23 and 24 in said control valves 12, 13 and 14, respectively. The relief valves 15 and 16 each have a leakage return oil line or conduit 15' and 16', respectively, associated therewith as represented by dotted lines in FIG, 1.

The combination or separation of the delivery of the said two pumps 1 and 2 for actuating either one or more of the three working cylinders 6, 7 and 8 is effected in the following manner: When, for instance, the control va ve 12 for the working cylinder 6, or more specifically, the valve spool of control valve 12 is from its neutral position moved toward the right or the left, the two control conduits 18 and 20 which have been united to the control conduit 21 are blocked. As a result, the circulation of both .pumps 1 and 2 is blocked by the relief valves 15 and 16,

and the delivery of the pump 1 passes through conduits 26 and 27 to the working cylinder 6, whereas the delivery of the pump 2 passes through conduits 28, 29, 30, 31, the check valve 32 and the conduits 33 and 27 to the working cylinder 6.

When now, for instance, the control valve 14 is additionally actuated by moving the same from its neutral position toward the right or toward the left, the passage of the oil under pressure delivered by the pump 2 from conduit 30 to conduit 31 is interrupted so that the delivery of pump 2 now passes through conduit 34 to the working cylinder 8. This combination possibility also applies to the flow between control valves 13 and 14 and the flow between control valves 12 and 13. In order to prevent a mutual pressure influence of the relief valves 15 and 16, check valves 17 and 19 are respectively arranged in the control conduits 18 and 20.

FIG. 2 shows in greater detail the passages in a control valve, for instance the control valve 12- Aswill be seen from FIG. 2, the valve spool 36 is reciprocable in the control valve housing 35. The housing 35 has pressed thereinto a bushing 37 which comprises one or more nozz e bores 38. When the valve spool 36 is actuated, in any con venient manner, for instance, hydraulically or mechanically, the nozzle bores 38 are first throttled by the inclined surfaces 39 and are subsequently shut off by control edge 40 or 41, respectively. As aresult, the control oil flow which enters the control valve 12 through bore 42 can be throttled in afine sensitive manner in order to be able in the precontrolled relief valves 15 and 16 to effect the division of the delivered oil flow in conformity with the requirements for the fine control of the consumer.

According to another embodiment of the invention illustrated in FIG. 3, the control housing, for instance, of the control valve 13 has screwed thereonto an intermediate housing. 43 in which an auxiliary valve spool 44 is displaceable mounted, Valve spool 44 rests by means of a spring dish 45 and spring 46 against the cover 47. The nozzle bores 48, the inclined surfaces 49, and the edges 50 have the same function as that of the respective members 38, 39 and 40 described above in connection with FIG. 2. The actuation of the main valve spool 36 in one direction is in the particular embodiment illustrated in the drawing effected by hydraulic control through the connection 51.

As will be evident from the above, the arrangement according to the present invention affords the possibility, without resorting to electrical or mechanical coupling members, in a purely hydraulic manner to combine any desired number of pump circuits of a corresponding number of consumers in any desired manner. In this way, for instance, when employing three-pump circuits, two out of four consumers will obtain the oil of all pumps if only one of said pump circuits is actuated, whereas a third consumer may be delivered only with the oil from two pumps anl the oil of the third pump will be available to the fourth or other consumers.

Referring further to the operation of the hydraulic system shown, adjustment of valve to cause a supply of fluid to the right-hand driving mechanism 4 will interrupt the connection of pump 2 to conduit 28 and will also interrupt the connection of check valve 19 with conduit 20. Pump 2 will thus deliver fluid solely to driving mechanism 4 only. Pump 1, at this time may continue to bypass to tank 25 via check valve 17 and conduits 18 and 21.

Similarly, shifting of valve 9 will cause pump 1 to deliver solely to left-hand driving mechanism 3, or shifting of valve 11 will cause pump 1 to deliver solely to swing mechanism 5. Valve 11 is effective only if valve 9 is not shifted. It will be seen that driving mechanisms 3 and 4 can be operated either independently or simultaneously but when both thereof are driven no other device can be actuated. Mechanism 5 can be actuated only when mechanism 3 is not actuated.

If none of mechanisms 3, 4 and 5 are actuated, any one or two of cylinders 6, 7 and 8 can be actuated, If either one of pumps 1 or 2 is cut off from its conduit 26, 28 by actuation of one of the valves 9, 10, 11, then any one only of cylinders 6, 7, 8 can be actuated by pressure from the other of the pumps.

In the case where none of valves 9, 10, 11 are shifted to supply their respective components, shifting of valve 13 will cause actuation of cylinder 7. Pump 2 will supply valve 13 directly through conduits 28 and 29, whereas pump 1 will supp yvalve 13 via conduits 26, 26a, 31, check valve 31:: and conduits 31b and 29 so that the supply of both pumps is delivered to piston 7. If, while valve 13 is shifted, either one of valves 12 or 14 is shifted, the respective piston 6, 8, will be actuated by fluid from pump 1. At this time, pump 2 supplies piston 7 only, while. pump 1 supplies one only of pistons 6, 8.

If, on the other hand, valve 14 is shifted to actuate piston 8, pump 2 will supply valve 14 via conduits 29 and 30 while pump 1 wi l also supply valve 14 via conduits 26 and 26a. It will be evident that a supply from one ofpumps 1, 2 to valve 14 will continue even if one or the other of valves 12, 13 is shifted to divert the supply of the other pu p- In still another case, if valve 12 is shifted, pump 1 will supply valve 12'directly while pump 2 will also supply valve 12 via conduits 29, 30, 31, check valve 32, and conduits 33 and 27; Shifting of either of valves 13 or 14 will cut off pump 2 from valve 12, while leaving pump l connected thereto, and will direct the fluid from pump 2 to the device pertaining to the shifted valve.

From the foregoing it will be seen that, when none of valves 9, 10, 11 are shifted, any one or two of pistons 6, 7, 8 can be actuated. When only one piston is actuated, both pumps supply fluid thereto and When-any .two pistons areactuated, each is supplied by a respective pump. H

FIGURE 4 illustrates schematically valve 15.lIn FIG- URE 4, the line from the pump is indicated at 70, and the line back to'the reservoir is indicated at 72. A valve mernber 74 is moveable upwardly to connect lines 70 and 72 when pump pressure becomes excessive, When valve 'mem-- ber 74 is in its FIGURE 4 position and all other valves are in neutral position, fluid passes from conduit 70 through restricted passage 76 to the lower side of valve 19 and therethrough. When a valve of the system is moved away from neutral position, fluid flow through valve 19 is interrupted. Thereafter, if,the pump pressure rises to an excessive amount, relief valve 78 will open and the pressure standing on the underside of piston 80 due to passage 82 will force the piston and valve member upwardly to connect lines 70 and 72, while shutting off passage 66. The restriction of passage 76 is greater than that of passage 82 so that after relief valve 78 opens, there will be an overpressure under piston 80 which will cause relief valve 15 to open. It is, of course, to be understood, that the present invention is, by no means, limited to the particular arrangement shown in the drawings, but also comprises any modifictions within the scope of the appended claims.

What is claimed is:

1. A hydraulic control circuit, especially for hydraulically actuated implements such as dredges and the like, comprising: pump means, a plurality of motor means to be actuated by pressure fluid from said pump means, control valve means for said motor means each having service port means connected to the'respective motor means and having pressure inlet port means and a movable valve member, each valve member having a first position wherein said service port means are disconnectedfrom said inlet port means and at least a second'position where-' in at least one of the-said service port means pertaining thereto is connected to said inlet port means, first bypass channel means leading from said pump means to exhaust and including a portion extending through each control valve means with said portions in series, second'channel' means leading from said pump means to the inlet port means of said control valve means and including a portion extending through each control valve means and interposed between the inlet port means of the respective control valve means and the inlet port means of the next following control valve means and with said portions in series, movement of any said valve members out of its said first position interrupting both-of the said portions of said first and second channels extending therethrough 2. A hydraulic control circuit according to claim '1 in which said pump means comprises first andsecorid pumps, said second channel means comprising a pera second one of said control valves, the said portion of.

said second channel means extending through the third one of said control valves being connected to both of said second channels, the portion of each said second channel leading from said third control valve to'the inlet port means of the next following control valve having a check valve therein opening away from said third con-- trol valve.

3. A hydraulic control circuit according to claim 2 in which a further valve means is interposed between each said pump and the inlet of the pertaining control valve, each said second channel including a portion extending through said further valve means of the pertaining pump and each further valve means interrupting the said portion when shifted to cause the supply of fluid to a connected motor, said first channel means including a portion pertaining to each pump which extends through the pertaining further valve means and which portion is interrupted upon shifting of the valve means to supply fluid to a connected motor, said last mentioned portions of said first channel means being in parallel and each having a check valve therein opening away from the pertaining pump.

4. A hydraulic control circuit according to claim 1 in which each control valve means has a housing in which the respective valve member is reciprocably mounted, said housing comprising a section having ports therein forming the inlet and outlet ends of the portion of said first channel means which extends therethrough, and auxiliary valve member means in said section and movable together with said first mentioned valve member and comprising an annular groove with inclined end portions, said groove registering with said ports in said section when said valve member is in its said first position and said inclined end portions throttling and then closing said ports as the valve member is shifted out of said first position thereof.

5. A hydraulic control circuit according to claim 4 in which each said port in said section is in the form of at least one nozzle bore.

6. A hydraulic control circuit according to claim 4 in which said section is in the form of a bushing inserted into said housing.

7. A hydraulic control circuit according to claim 4 in which said section is mounted on the end of said housing and includes means for receiving pilot fluid for shifting said valve member in one direction. 1

References Cited UNITED STATES PATENTS 2,244,213 6/1941 Patton. 2,319,551 5/1943 Linden et a1. -52 XR 3,146,593 9/1964 Stacey. 3,156,098 11/1964 La ROll 9l--411XR EDGAR W. GEOGHEGAN, Primary Examiner US. Cl. X.R. 6097; 91-414 

